Computational modeling is a powerful tool for studying and investigating the behavior of fluidized bed gasifiers and the modeling of the initial devolatilization step is necessary to provide a reliable description of the whole process involving the feedstock decomposition and the subsequent gasification reaction. In this work, a bench-scale fluidized bed reactor was used to examine the devolatilization of different carbonaceous materials within the temperature range from 650 to 850 °C. The experimental test campaign was used to derive the linear correlation factor to describe the devolatilization in terms of product distribution as a function of temperature and highlight the different behavior between lignocellulosic and plastic feedstocks. Furthermore, the experimental data were used to develop concise kinetic expressions able to fit the experimental devolatilization times ranging from 75 in the case of poplar at a lower temperature and 22 s for the Organic Fraction of Municipal Solid Waste (OFMSW) at a higher temperature. The obtained model produces a simple kinetic expression where the size of the particle is enclosed in the kinetic parameters. The kinetic model sided by the application of linear correlations describes the overall thermal decomposition in a fluidized bed, simplifying its modeling in commercial simulation software, even when particles are considered as point-like bodies.

Gasification of plastic waste is an emerging technology of particular interest to the scientific world given the production of a hydrogen-rich gas from waste material. Devolatilization is a first step thermochemical decomposition process which is crucial in determining the quality of the gas in the whole gasification process. The devolatilization of polypropylene (a key compound of plastic waste) has been investigated experimentally in a bench-scale fluidized bed reactor. Experimental tests were carried out by varying two key parameters of the process—the size of the polypropylene spheres (8–12 mm) and temperature (650–850 °C). Temperature shows the highest influence on the process. Greater molecular cracking results were more pronounced at higher temperatures, increasing the production of light hydrocarbons along with the formation of solid carbon residue and tar. The overall syngas output reduced, while the H₂ content increased. Furthermore, a pseudo-first-order kinetic model was developed to describe the devolatilization process (E_app = 11.8 kJ/mol, A₁ = 0.55 s⁻¹, ψ = 0.77).

This study focuses on the modeling, simulation, and optimization of an integrated biomass gasification and methanation process to produce bio-synthetic natural gas (Bio-SNG) as part of the AIRE project. The process was simulated using Aspen Plus^® software (V14), incorporating experimental results from pilot-scale gasification setups. Key steps involved syngas production in a dual fluidized bed gasifier and its subsequent conversion to Bio-SNG in a methanation section. Heat integration strategies were implemented to enhance system results demonstrate that optimized heat recovery, achieved by utilizing exothermic methanation reactions to preheat gasification inputs, eliminates the need for auxiliary fuel in the gasification process. The optimized system achieved a thermal recovery rate of 80%, a cold gas efficiency of 79%, a Bio-SNG production rate of 0.4 Nm³/kg_Biom, and a methane content of 85 vol.%. These optimizations reduced CO₂ emissions by 10% while increasing overall energy efficiency. This work highlights the potential of integrating biomass gasification and methanation processes with heat recovery for sustainable methane production. The findings provide a basis for scaling up the process and further exploring syngas utilization pathways to produce renewable energy carriers.

Population growth and economic development significantly increased plastic consumption, leading to a rise in plastic waste (PW) generation. Only a small fraction of this waste is currently recycled, with the majority being landfilled or released into the environment. Among emerging waste management strategies, chemical recycling through gasification stands out for its flexibility and potential to valorise non-recyclable plastic fractions. This study investigates the steam gasification of a representative PW mixture in a bench-scale fluidized bed reactor operated at 850 °C, equipped with a ceramic filter candle in the freeboard for in-situ hot-gas cleaning. At a steam-to-plastic ratio of 1.5, the process produced 2.4 Nm³/kg_PW of nitrogen-free gas containing over 50 vol% hydrogen. The introduction of a commercial Ni-based catalyst reduced tar content by 70%, increased gas yield above 3 Nm³ kg⁻¹PW, and raised hydrogen concentration to about 56 vol%. Building upon these results, an Aspen Plus model was developed to evaluate system integration of steam gasification for synthetic natural gas (SNG) production. The simulation confirmed the feasibility of converting plastic-derived syngas into high-purity SNG with a yield of approximately 0.9 kg_SNG/kg_PW, and an overall thermal efficiency of 93.5% after process optimization and heat recovery. The combined experimental and modelling results demonstrate that catalytic steam gasification represents a technically viable and sustainable waste-to-fuel pathway, enabling the conversion of mixed PW into recycled carbon syngas and SNG within future circular and low-carbon energy systems.